The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x bee448390e5166d019e9e037194d487ee94399d9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023102913-mutate-envelope-6e98@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From bee448390e5166d019e9e037194d487ee94399d9 Mon Sep 17 00:00:00 2001 From: Linus Walleij <linus.walleij@xxxxxxxxxx> Date: Sat, 2 Sep 2023 21:46:20 +0200 Subject: [PATCH] iio: afe: rescale: Accept only offset channels As noted by Jonathan Cameron: it is perfectly legal for a channel to have an offset but no scale in addition to the raw interface. The conversion will imply that scale is 1:1. Make rescale_configure_channel() accept just scale, or just offset to process a channel. When a user asks for IIO_CHAN_INFO_OFFSET in rescale_read_raw() we now have to deal with the fact that OFFSET could be present but SCALE missing. Add code to simply scale 1:1 in this case. Link: https://lore.kernel.org/linux-iio/CACRpkdZXBjHU4t-GVOCFxRO-AHGxKnxMeHD2s4Y4PuC29gBq6g@xxxxxxxxxxxxxx/ Fixes: 53ebee949980 ("iio: afe: iio-rescale: Support processed channels") Fixes: 9decacd8b3a4 ("iio: afe: rescale: Fix boolean logic bug") Reported-by: Jonathan Cameron <jic23@xxxxxxxxxx> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx> Reviewed-by: Peter Rosin <peda@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230902-iio-rescale-only-offset-v2-1-988b807754c8@xxxxxxxxxx Cc: <Stable@xxxxxxxxxxxxxxx> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 1f280c360701..56e5913ab82d 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -214,8 +214,18 @@ static int rescale_read_raw(struct iio_dev *indio_dev, return ret < 0 ? ret : -EOPNOTSUPP; } - ret = iio_read_channel_scale(rescale->source, &scale, &scale2); - return rescale_process_offset(rescale, ret, scale, scale2, + if (iio_channel_has_info(rescale->source->channel, + IIO_CHAN_INFO_SCALE)) { + ret = iio_read_channel_scale(rescale->source, &scale, &scale2); + return rescale_process_offset(rescale, ret, scale, scale2, + schan_off, val, val2); + } + + /* + * If we get here we have no scale so scale 1:1 but apply + * rescaler and offset, if any. + */ + return rescale_process_offset(rescale, IIO_VAL_FRACTIONAL, 1, 1, schan_off, val, val2); default: return -EINVAL; @@ -280,8 +290,9 @@ static int rescale_configure_channel(struct device *dev, chan->type = rescale->cfg->type; if (iio_channel_has_info(schan, IIO_CHAN_INFO_RAW) && - iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE)) { - dev_info(dev, "using raw+scale source channel\n"); + (iio_channel_has_info(schan, IIO_CHAN_INFO_SCALE) || + iio_channel_has_info(schan, IIO_CHAN_INFO_OFFSET))) { + dev_info(dev, "using raw+scale/offset source channel\n"); } else if (iio_channel_has_info(schan, IIO_CHAN_INFO_PROCESSED)) { dev_info(dev, "using processed channel\n"); rescale->chan_processed = true;
